Research Article
Damage Detection on Sudden Stiffness Reduction Based on Discrete Wavelet Transform
Table 1
Natural frequency before and after sudden damage.
| | Damage extent | Frequencies (Hz) | | | | | |
| | 0% | 2.513 | 7.335 | 11.563 | 14.854 | 16.941 | | 1% | 2.508 (−0.18%) | 7.324 (−0.15%) | 11.55 (−0.11%) | 14.85 (−0.05%) | 16.94 (−0.01%) | | 2% | 2.504 (−0.36%) | 7.313 (−0.30%) | 11.54 (−0.21%) | 14.84 (−0.11%) | 16.94 (−0.03%) | | 5% | 2.490 (−0.94%) | 7.278 (−0.78%) | 11.50 (−0.53%) | 14.81 (−0.26%) | 16.93 (−0.07%) | | 10% | 2.464 (−1.97%) | 7.218 (−1.62%) | 11.44 (−1.06%) | 14.78 (−0.52%) | 16.92 (−0.14%) | | 20% | 2.407 (−4.41%) | 7.088 (−3.48%) | 11.32 (−2.18%) | 14.71 (−1.01%) | 16.90 (−0.26%) | | 40% | 2.253 (−11.6%) | 6.781 (−8.16%) | 11.07 (−4.50%) | 14.57 (−1.92%) | 16.86 (−0.46%) |
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Note: values in brackets are the percentage of change in natural frequency.
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